The present invention relates to vehicle visors, and more particularly to a visor including an illuminated vanity mirror with a lens for uniformly distributing light onto a person's face.
Modern vehicles often include illuminated vanity mirrors mounted on sun visors in the passenger compartment of the vehicle. The lighted vanity mirrors include light sources and lens configured to provide light at a sufficient intensity and uniformity so that, for example, facial makeup can be applied by a user under low ambient light conditions. Various lighting configurations have been used with varying degrees of success. U.S. Pat. Nos. 4,486,819; 4,421,355 and 4,227,241 represent a few approaches that have been employed. Further improvements, however, are desired to provide better control over the size and uniformity of the light distribution from an illuminated visor along with a reduction in stray light and glare.
In particular, "prism" and "pillow" optics technology have been used in lenses of vehicle interior lighting accessories, in an effort to improve the uniformity of the light patterns formed by the lighting accessories. Prism optics technology, also called V-groove optics technology, uses a plurality of elongated triangularly-shaped prismatic surfaces to direct individual sections of light in desired directions as shown, for example, in the prior art of FIGS. 1-5. Pillow optics technology uses a plurality of small, dish-shaped depressions or protrusions on a lens surface to direct individual sections of light in desired directions as seen in FIG. 6. In effect, each dish-shaped depression or protrusion acts like a mini magnifying glass to direct the light in a predetermined direction. The size of these depressions or protrusions, their radii, and their relative orientation is predetermined through relatively extensive testing to achieve an acceptable pattern of light. The individual depressions can be substantially any size desired, but usually are in the range of about 1 mm.times.1 mm to about 2 mm.times.3 mm.
There are several particular problems associated with pillow optics lenses and prism optics lenses. These lens characteristically produce non-uniform light patterns such as glare, which is blinding, dazzling spots of light; "spider webbing," which is randomly oriented fine streaks of bright light having the appearance of a spider web; light/dark patchiness, which is relatively bright regions and adjacent relatively dark regions within the overall pattern; and chromatic aberrations, which are rainbow-like colored patterns at the edges of the lighted pattern.
With prism and pillow optics technology, it is possible to design individual sections of the lens to redistribute light from bright areas toward dark areas. However, it is typically not possible to control light rays sufficiently to eliminate non-uniformities in the light patterns. Such non-uniform light patterns are irritating to the human eye and make it difficult to use the light for very long or for fine tasks such as for applying makeup. Further, it is not uncommon to spend many hours of design, testing and redesign time in lenses incorporating these technologies to arrive at an acceptable light pattern before acceptable prototypes can be made. In the highly competitive automotive industry, such extensive testing and design time adds excessive cost to a product and can delay the introduction of new products.
Also, a lens including prism or pillow optics technology has a multi-surfaced crystal-like appearance that frequently does not compliment the non-glossy decor of the vanity mirror frame or other components in the vehicle passenger compartment, thus creating a less than desirable mismatched appearance. Nonetheless, lens including prism and pillow optics technology are generally accepted by the industry as two of the preferred ways of controlling/dispersing light into a predetermined pattern.
Another characteristic of prism and pillow optics technology is that these types of lenses must be spaced significantly from the light source in order to be effective. This results in a relatively thicker product, which is undesirable since passenger headroom is a problem in vehicle passenger compartments, especially in view of the proximity of a visor to a vehicle occupant's head to a visor in modern vehicles with radically sloped windshields and in view of governmental standards relating to occupant safety such as for crash testing. Additionally, the proximity of a pair of spaced vanity mirror light sources to a person's eyes can make it difficult for a vehicle passenger to see himself or herself since the lens spacing is close to that of the inter pupillary distance of a human's eyes. The inventors have discovered that bright spots can cause serious difficulty when trying to see one's self properly in such an illuminated vanity mirror. Still further, non-uniformity of light distribution, e.g. light and dark areas, also make it difficult to effectively use a visor vanity mirror. Therefore, an illuminated vanity mirror visor for uniformly illuminating a person's face and solving the aforementioned problems is desired.